math: matrix: Add transform-x and transform-y procedures.

* chickadee/math/matrix.scm (transform-x, transform-y): New procedures.

1 files changed, 17 insertions, 8 deletions

diff --git a/chickadee/math/matrix.scm b/chickadee/math/matrix.scm
index 00f5849..3e73f0c 100644
--- a/chickadee/math/matrix.scm
+++ b/chickadee/math/matrix.scm
@@ -45,6 +45,8 @@
             matrix4-rotate-z!
             matrix4-rotate-z
             matrix4-2d-transform!
+            transform-x
+            transform-y
             transform!))
 
 ;; 4x4 matrix
@@ -419,13 +421,20 @@ happens with respect to ORIGIN, a 2D vector."
         (f32vector-set! bv 12 (- x (* ox q) (* oy s)))
         (f32vector-set! bv 13 (- y (* ox r) (* oy t)))))))
 
+(define-inlinable (transform-x matrix x y)
+  (let ((bv (matrix4-bv matrix)))
+    (+ (* x (matrix-ref bv 0 0))
+       (* y (matrix-ref bv 1 0))
+       (matrix-ref bv 3 0))))
+
+(define-inlinable (transform-y matrix x y)
+  (let ((bv (matrix4-bv matrix)))
+    (+ (* x (matrix-ref bv 0 1))
+       (* y (matrix-ref bv 1 1))
+       (matrix-ref bv 3 1))))
+
 (define-inlinable (transform! matrix v)
-  (let ((bv (matrix4-bv matrix))
-        (x (vec2-x v))
+  (let ((x (vec2-x v))
         (y (vec2-y v)))
-    (set-vec2-x! v (+ (* x (matrix-ref bv 0 0))
-                      (* y (matrix-ref bv 1 0))
-                      (matrix-ref bv 3 0)))
-    (set-vec2-y! v (+ (* x (matrix-ref bv 0 1))
-                      (* y (matrix-ref bv 1 1))
-                      (matrix-ref bv 3 1)))))
+    (set-vec2-x! v (transform-x matrix x y))
+    (set-vec2-y! v (transform-y matrix x y))))